Laser has the advantages of high brightness, directivity, energy, and beam quality. In recent years, laser technology has been widely used in industrial sensing, communication, and medical treatment, particularly in treating vascular diseases. Thrombosis is a serious vascular disease with a complicated pathogenesis. Thrombosis can cause blood clots in blood vessels, resulting in insufficient blood supply to vital organs. Ischemic stroke is an acute cerebrovascular disease, mainly occasioned by atherosclerosis of the arteries supplying blood to the brain, which in turn results in blockage of blood vessels and insufficient blood supply to the brain; long-term obstruction can lead to brain tissue necrosis. If a blood clot flows into the heart, it can cause a myocardial infarction. Moreover, if lower extremity thrombosis is serious, it can cause a blood circulation disorder at the end of the extremity and even gangrene. Venous vascular injury, endothelial dysfunction, and slow blood flow are all critical factors in developing deep vein thrombosis. Severe consequences of deep vein thrombosis can lead to pulmonary embolism and amputation. Therefore, thrombus is a vascular disease that seriously endangers human life, health, and safety, and its treatment is the fundamental method for recovery.

The rapid development of laser technology has promoted research progress in laser medical treatment. In particular, pulsed laser has broad application prospects in the fields of industry, medicine, and communication owing to its high repetition rate, energy peak power, and beam quality. The effect of laser on thrombus is mainly realized by the photothermal, photochemical, and photomechanical effects between the thrombus and biological tissue to achieve laser thrombolysis. Laser thrombolysis has the advantage of accurate localization, which can eliminate the thrombus at the site of the blood vessels, restore blood flow, avoid severe injury caused by surgery, and reduce postoperative complications. Because the ablation time is short, postoperative patients recover quickly and reduce hospital stay and medical costs. Therefore, the study of laser thrombolysis is of great significance.

With the development of laser technology and the continuous improvement of the interaction mechanism between laser and biological tissue, the application of laser in thrombus ablation has progressed in some aspects. With the same sample and conditions, the thermal cautery of continuous-wave laser to tissue is significantly higher than that of a pulsed laser. Hence, a pulsed laser is mostly used in laser thrombolysis to avoid unnecessary damage to surrounding tissue. Optimization of pulsed-laser parameters—such as wavelength, pulse width, power, and energy—is the future development direction of pulsed-laser thrombolysis. Furthermore, in laser thrombolysis, the direct use of bare optical fibers to generate laser has certain adverse effects on biological tissues, whereas the use of radial fibers requires lower energy, which significantly reduces the adverse effects. Consequently, various launch fibers have been developed. Moreover, laser thrombolysis combined with various other thrombolysis methods, such as mechanical thrombectomy, can increase the success rate of surgery and reduce the recurrence rate of restenosis, which is of great significance for thrombolysis. In-vitro and clinical tests have shown that the light emitted by 308 nm and 355 nm excimer lasers is a cold light source that generates less heat and penetrates less deeply into tissues, especially for calcified thrombus. Several studies support this conclusion. The use of multiple laser wavelengths to ablate thrombi has also been verified by various experiments. Different wavelengths of lasers absorb different tissue components differently and have specific ablation effects on different thrombus types and sites. Therefore, many research institutions have studied and developed multi-band laser thrombolytics.

This paper reviews the application status of laser in the treatment of thrombosis, mainly from in-vitro and clinical settings. Further, it summarizes the application progress of laser thrombolysis and the possible future development direction. Currently, research on laser medical treatment is developing in the direction of multi-band and multi-application fields. Meanwhile, laser technologies such as multi-fiber and multi-diameter types are being developed to reduce the incidence of complications. For excimer lasers, realizing high power, full fiber structure, and low cost is the main research prospect. Moreover, deepening the research on the mechanism of interaction between laser and tissue while understanding every process and stage of organizational change can optimize the laser parameters to realize real-time adjustment and dynamically control the process of laser thrombolysis. This forms an essential part of theoretical research to guide the actual application process.